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astroengine writes "Scientists have found a system of planets that appears to have survived being engulfed by their dying parent star. The discovery raises questions about the ultimate fate of our solar system when the sun runs out of hydrogen gas in about 5 billion years and violently transform into an expanding red giant star. Scientists believe all the planets from Earth inward will be destroyed when the sun expands, but new research suggests that if planets are large enough, they may outlast their parent star's death, even if they are engulfed."

Sobering up now, this "dead star" is really a white dwarf, isn't it?Time scales become truly mind-boggling when, after eons as a white dwarf, the nuclear reaction peters out, the "ember" still emitting heat for eons upon eons.

If the proton decays, when the last white dwarf goes out, around 10^14 years from now, the Universe passes from the Stelliferous Era to the Degenerate Era, everything slowly cooling down, matter slowly disintegrating or being sucked into black holes, beyond the point when all free-floating matter has reached 1-to-1 odds of evaporating, roughly 10^40 years from now.

If the proton decays, then the Universe enters the Black Hole Era, when there is no more matter to be sucked into singularities, so that they now begin the excruciatingly slow process of evaporating via Hawking Radiation. The last of the supermassive black holes will have evaporated by 10^100 from now. Then we enter a period of virtual infinity, named the Dark Era, the Universe inconceivably vast and empty and still accelerating.

However, if the proton does NOT decay, circumstances and numbers become even more surreal/nasty, all stars NOT sucked into black holes reach 1-to-1 odds of becoming iron spheres at around 10^1500 years from now. That's right, all baryonic matter in the Universe will have frozen into an iron state. Finally, the last iron star will collapse into a neutron star or black hole at 10^10^76 (ten to the ten to the seventy six).

That's not true, actually. You see, beyond the accelerating universe, by the time of the end of which you speak, we will have built... "God", for lack of a better word. By that time, we have looked at each particle and each vibration of each string and determined where it came from and where it is going (yes, there's no random), allowing us to calculate everything back to before the big bang.

Everything will be known - every path of every falling leaf anywhere in the universe, ever. Every action, every thought and every feeling of every creature that ever lived will be known, in effect raising everyone from the dead in a big collective consciousness beyond this universe and all the matter and energy in it. Thankfully there must have been a universe about around here before, because out there on the outside, was matter we could build our collective of. We need all the matter in this universe. We need to start it again, in the exact same way it once started. Everything in this universe will all happen exactly as it happened and is happening and will happen once more.

Why we need to do that? I'll get into that later, unless I've all ready mentioned it before. But now I have to go. These are very hectic days for this weary "time-traveler". My adventures on this earth at this point in history are not that important. They are dwarfed by the cosmic storyline, but they might be an amusing read if I get time to write about them.

Did they find planets orbiting a white dwarf at orbits that would have been inside the red giant, did they find planets orbiting a red giant or did they find planets orbiting inside the red giant? Is the star dead or dying? TFA doesn't seem to say anything about the former, and conflicts with TFS about the latter.

Because probability dictates a good chance of a Futurama-like world will exist sometime during that span. If you want to be a part get started on your own stasis chamber, now. Don't forget to take a pizza with you, so you'll have something to eat when you emerge.

In the meanwhile, I'm more worried about the survivors of those dead worlds, who are on their way here.

In my case, I was wondering if somebody would mention if the lack of a "permanent" energy source like the Sun would spell the death of our planet anyway, if the dying, expanding Sun didn't get rid of it first after all.

So will my grave still exist on whats left on a scorched rock -- or not? You seem to want to have it both ways. Seems like you switched specifically to disagree with me. I used this to illustrate to "having it both ways" to my wife, who uses this tactic all too often;)

The expansion phase is extremely short on those time scales. A star will typically remain a red giant for a few million years [berkeley.edu]. Its surface temperature at that time will be only around 5000K, which is hot enough to evaporate the planet eventually, but not by orders of magnitude. The red giant has low density, so the heat exchange takes longer.All in all, it's not inconceivable that a planet's core might remain intact if it's on the very edge of expansion.

Nothing, except many of its inhabitants are short-sighted, selfish, petty, nimrods, who only care about themselves and what effects them directly, and they are, to a great extent, the ones in charge/power making decisions that affect the rest.

I'm sorry, but giving something like only 2000 years as a timescale for the Earth becoming "uninhabitable by life as we know it" due just to increases in solar output is just wildly inaccurate. The Sun is not changing that fast.

I'd say 100 million years is about a short as you can credibly go, and obviously life will evolve during that time. The real killer would be the point at which liquid water can no longer exist on the surface, and that's more like a billion years in the future.

In 800 million year to 1 billion year the sun luminosity will have increased so much as to make existence of life and even water in liquid form a rarity on earth, baring complete extinction.

As for those purporting we should think about earth extinguishing and prepare the way for a futurama like civilisation : 1) we aren't able to even get agreement on something as simple as CO2 and GCC which is a threat *now*2) we are still eating oil like tehre is no tomorow. And the way I see it : there won't be, because if we don't find an alternative source like fusion, our age of tech will *end* and there won't be another one *ever* (too much research depend on plentyful energy , so to regain back what we had, would be next to impossible)